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dump1090/net_io.c
Malcolm Robb 24080a22b1 antirez 
Free the client on best effort write(2) short write
2014-02-22 22:35:42 +00:00

884 lines
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// dump1090, a Mode S messages decoder for RTLSDR devices.
//
// Copyright (C) 2012 by Salvatore Sanfilippo <antirez@gmail.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
#include "dump1090.h"
//
// ============================= Networking =============================
//
// Note: here we disregard any kind of good coding practice in favor of
// extreme simplicity, that is:
//
// 1) We only rely on the kernel buffers for our I/O without any kind of
// user space buffering.
// 2) We don't register any kind of event handler, from time to time a
// function gets called and we accept new connections. All the rest is
// handled via non-blocking I/O and manually polling clients to see if
// they have something new to share with us when reading is needed.
//
//=========================================================================
//
// Networking "stack" initialization
//
void modesInitNet(void) {
struct {
char *descr;
int *socket;
int port;
} services[MODES_NET_SERVICES_NUM] = {
{"Raw TCP output", &Modes.ros, Modes.net_output_raw_port},
{"Raw TCP input", &Modes.ris, Modes.net_input_raw_port},
{"Beast TCP output", &Modes.bos, Modes.net_output_beast_port},
{"Beast TCP input", &Modes.bis, Modes.net_input_beast_port},
{"HTTP server", &Modes.https, Modes.net_http_port},
{"Basestation TCP output", &Modes.sbsos, Modes.net_output_sbs_port}
};
int j;
memset(Modes.clients,0,sizeof(Modes.clients));
Modes.maxfd = -1;
for (j = 0; j < MODES_NET_SERVICES_NUM; j++) {
int s = anetTcpServer(Modes.aneterr, services[j].port, NULL);
if (s == -1) {
fprintf(stderr, "Error opening the listening port %d (%s): %s\n",
services[j].port, services[j].descr, strerror(errno));
exit(1);
}
anetNonBlock(Modes.aneterr, s);
*services[j].socket = s;
}
signal(SIGPIPE, SIG_IGN);
}
//
//=========================================================================
//
// This function gets called from time to time when the decoding thread is
// awakened by new data arriving. This usually happens a few times every second
//
void modesAcceptClients(void) {
int fd, port;
unsigned int j;
struct client *c;
int services[6];
services[0] = Modes.ros;
services[1] = Modes.ris;
services[2] = Modes.bos;
services[3] = Modes.bis;
services[4] = Modes.https;
services[5] = Modes.sbsos;
for (j = 0; j < sizeof(services)/sizeof(int); j++) {
fd = anetTcpAccept(Modes.aneterr, services[j], NULL, &port);
if (fd == -1) continue;
if (fd >= MODES_NET_MAX_FD) {
close(fd);
return; // Max number of clients reached
}
anetNonBlock(Modes.aneterr, fd);
c = (struct client *) malloc(sizeof(*c));
c->service = services[j];
c->fd = fd;
c->buflen = 0;
Modes.clients[fd] = c;
anetSetSendBuffer(Modes.aneterr,fd,MODES_NET_SNDBUF_SIZE);
if (Modes.maxfd < fd) Modes.maxfd = fd;
if (services[j] == Modes.sbsos) Modes.stat_sbs_connections++;
if (services[j] == Modes.ros) Modes.stat_raw_connections++;
if (services[j] == Modes.bos) Modes.stat_beast_connections++;
j--; // Try again with the same listening port
if (Modes.debug & MODES_DEBUG_NET)
printf("Created new client %d\n", fd);
}
}
//
//=========================================================================
//
// On error free the client, collect the structure, adjust maxfd if needed.
//
void modesFreeClient(int fd) {
close(fd);
if (Modes.clients[fd]->service == Modes.sbsos) {
if (Modes.stat_sbs_connections) Modes.stat_sbs_connections--;
}
else if (Modes.clients[fd]->service == Modes.ros) {
if (Modes.stat_raw_connections) Modes.stat_raw_connections--;
}
else if (Modes.clients[fd]->service == Modes.bos) {
if (Modes.stat_beast_connections) Modes.stat_beast_connections--;
}
free(Modes.clients[fd]);
Modes.clients[fd] = NULL;
if (Modes.debug & MODES_DEBUG_NET)
printf("Closing client %d\n", fd);
// If this was our maxfd, scan the clients array to find the new max.
// Note that we are sure there is no active fd greater than the closed
// fd, so we scan from fd-1 to 0.
if (Modes.maxfd == fd) {
int j;
Modes.maxfd = -1;
for (j = fd-1; j >= 0; j--) {
if (Modes.clients[j]) {
Modes.maxfd = j;
break;
}
}
}
}
//
//=========================================================================
//
// Send the specified message to all clients listening for a given service
//
void modesSendAllClients(int service, void *msg, int len) {
int j;
struct client *c;
for (j = 0; j <= Modes.maxfd; j++) {
c = Modes.clients[j];
if (c && c->service == service) {
int nwritten = write(j, msg, len);
if (nwritten != len) {
modesFreeClient(j);
}
}
}
}
//
//=========================================================================
//
// Write raw output in Beast Binary format with Timestamp to TCP clients
//
void modesSendBeastOutput(struct modesMessage *mm) {
char *p = &Modes.beastOut[Modes.beastOutUsed];
int msgLen = mm->msgbits / 8;
char * pTimeStamp;
int j;
*p++ = 0x1a;
if (msgLen == MODES_SHORT_MSG_BYTES)
{*p++ = '2';}
else if (msgLen == MODES_LONG_MSG_BYTES)
{*p++ = '3';}
else if (msgLen == MODEAC_MSG_BYTES)
{*p++ = '1';}
else
{return;}
pTimeStamp = (char *) &mm->timestampMsg;
for (j = 5; j >= 0; j--) {
*p++ = pTimeStamp[j];
}
*p++ = mm->signalLevel;
memcpy(p, mm->msg, msgLen);
Modes.beastOutUsed += (msgLen + 9);
if (Modes.beastOutUsed >= Modes.net_output_raw_size)
{
modesSendAllClients(Modes.bos, Modes.beastOut, Modes.beastOutUsed);
Modes.beastOutUsed = 0;
Modes.net_output_raw_rate_count = 0;
}
}
//
//=========================================================================
//
// Write raw output to TCP clients
//
void modesSendRawOutput(struct modesMessage *mm) {
char *p = &Modes.rawOut[Modes.rawOutUsed];
int msgLen = mm->msgbits / 8;
int j;
unsigned char * pTimeStamp;
if (Modes.mlat && mm->timestampMsg) {
*p++ = '@';
pTimeStamp = (unsigned char *) &mm->timestampMsg;
for (j = 5; j >= 0; j--) {
sprintf(p, "%02X", pTimeStamp[j]);
p += 2;
}
Modes.rawOutUsed += 12; // additional 12 characters for timestamp
} else
*p++ = '*';
for (j = 0; j < msgLen; j++) {
sprintf(p, "%02X", mm->msg[j]);
p += 2;
}
*p++ = ';';
*p++ = '\n';
Modes.rawOutUsed += ((msgLen*2) + 3);
if (Modes.rawOutUsed >= Modes.net_output_raw_size)
{
modesSendAllClients(Modes.ros, Modes.rawOut, Modes.rawOutUsed);
Modes.rawOutUsed = 0;
Modes.net_output_raw_rate_count = 0;
}
}
//
//=========================================================================
//
// Write SBS output to TCP clients
// The message structure mm->bFlags tells us what has been updated by this message
//
void modesSendSBSOutput(struct modesMessage *mm) {
char msg[256], *p = msg;
uint32_t offset;
struct timeb epocTime;
struct tm stTime;
int msgType;
//
// SBS BS style output checked against the following reference
// http://www.homepages.mcb.net/bones/SBS/Article/Barebones42_Socket_Data.htm - seems comprehensive
//
// Decide on the basic SBS Message Type
if ((mm->msgtype == 4) || (mm->msgtype == 20)) {
msgType = 5;
} else if ((mm->msgtype == 5) || (mm->msgtype == 21)) {
msgType = 6;
} else if ((mm->msgtype == 0) || (mm->msgtype == 16)) {
msgType = 7;
} else if (mm->msgtype == 11) {
msgType = 8;
} else if ((mm->msgtype != 17) && (mm->msgtype != 18)) {
return;
} else if ((mm->metype >= 1) && (mm->metype <= 4)) {
msgType = 1;
} else if ((mm->metype >= 5) && (mm->metype <= 8)) {
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID)
{msgType = 2;}
else
{msgType = 7;}
} else if ((mm->metype >= 9) && (mm->metype <= 18)) {
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID)
{msgType = 3;}
else
{msgType = 7;}
} else if (mm->metype != 19) {
return;
} else if ((mm->mesub == 1) || (mm->mesub == 2)) {
msgType = 4;
} else {
return;
}
// Fields 1 to 6 : SBS message type and ICAO address of the aircraft and some other stuff
p += sprintf(p, "MSG,%d,111,11111,%06X,111111,", msgType, mm->addr);
// Fields 7 & 8 are the current time and date
if (mm->timestampMsg) { // Make sure the records' timestamp is valid before outputing it
epocTime = Modes.stSystemTimeBlk; // This is the time of the start of the Block we're processing
offset = (int) (mm->timestampMsg - Modes.timestampBlk); // This is the time (in 12Mhz ticks) into the Block
offset = offset / 12000; // convert to milliseconds
epocTime.millitm += offset; // add on the offset time to the Block start time
if (epocTime.millitm > 999) // if we've caused an overflow into the next second...
{epocTime.millitm -= 1000; epocTime.time ++;} // ..correct the overflow
stTime = *localtime(&epocTime.time); // convert the time to year, month day, hours, min, sec
p += sprintf(p, "%04d/%02d/%02d,", (stTime.tm_year+1900),(stTime.tm_mon+1), stTime.tm_mday);
p += sprintf(p, "%02d:%02d:%02d.%03d,", stTime.tm_hour, stTime.tm_min, stTime.tm_sec, epocTime.millitm);
} else {
p += sprintf(p, ",,");
}
// Fields 9 & 10 are the current time and date
ftime(&epocTime); // get the current system time & date
stTime = *localtime(&epocTime.time); // convert the time to year, month day, hours, min, sec
p += sprintf(p, "%04d/%02d/%02d,", (stTime.tm_year+1900),(stTime.tm_mon+1), stTime.tm_mday);
p += sprintf(p, "%02d:%02d:%02d.%03d", stTime.tm_hour, stTime.tm_min, stTime.tm_sec, epocTime.millitm);
// Field 11 is the callsign (if we have it)
if (mm->bFlags & MODES_ACFLAGS_CALLSIGN_VALID) {p += sprintf(p, ",%s", mm->flight);}
else {p += sprintf(p, ",");}
// Field 12 is the altitude (if we have it) - force to zero if we're on the ground
if ((mm->bFlags & MODES_ACFLAGS_AOG_GROUND) == MODES_ACFLAGS_AOG_GROUND) {
p += sprintf(p, ",0");
} else if (mm->bFlags & MODES_ACFLAGS_ALTITUDE_VALID) {
p += sprintf(p, ",%d", mm->altitude);
} else {
p += sprintf(p, ",");
}
// Field 13 and 14 are the ground Speed and Heading (if we have them)
if (mm->bFlags & MODES_ACFLAGS_NSEWSPD_VALID) {p += sprintf(p, ",%d,%d", mm->velocity, mm->heading);}
else {p += sprintf(p, ",,");}
// Fields 15 and 16 are the Lat/Lon (if we have it)
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID) {p += sprintf(p, ",%1.5f,%1.5f", mm->fLat, mm->fLon);}
else {p += sprintf(p, ",,");}
// Field 17 is the VerticalRate (if we have it)
if (mm->bFlags & MODES_ACFLAGS_VERTRATE_VALID) {p += sprintf(p, ",%d", mm->vert_rate);}
else {p += sprintf(p, ",");}
// Field 18 is the Squawk (if we have it)
if (mm->bFlags & MODES_ACFLAGS_SQUAWK_VALID) {p += sprintf(p, ",%x", mm->modeA);}
else {p += sprintf(p, ",");}
// Field 19 is the Squawk Changing Alert flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_FS_VALID) {
if ((mm->fs >= 2) && (mm->fs <= 4)) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
// Field 20 is the Squawk Emergency flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_SQUAWK_VALID) {
if ((mm->modeA == 0x7500) || (mm->modeA == 0x7600) || (mm->modeA == 0x7700)) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
// Field 21 is the Squawk Ident flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_FS_VALID) {
if ((mm->fs >= 4) && (mm->fs <= 5)) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
// Field 22 is the OnTheGround flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_AOG_VALID) {
if (mm->bFlags & MODES_ACFLAGS_AOG) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
p += sprintf(p, "\r\n");
modesSendAllClients(Modes.sbsos, msg, p-msg);
}
//
//=========================================================================
//
void modesQueueOutput(struct modesMessage *mm) {
if (Modes.stat_sbs_connections) {modesSendSBSOutput(mm);}
if (Modes.stat_beast_connections) {modesSendBeastOutput(mm);}
if (Modes.stat_raw_connections) {modesSendRawOutput(mm);}
}
//
//=========================================================================
//
// This function decodes a Beast binary format message
//
// The message is passed to the higher level layers, so it feeds
// the selected screen output, the network output and so forth.
//
// If the message looks invalid it is silently discarded.
//
// The function always returns 0 (success) to the caller as there is no
// case where we want broken messages here to close the client connection.
//
int decodeBinMessage(struct client *c, char *p) {
int msgLen = 0;
unsigned char msg[MODES_LONG_MSG_BYTES];
struct modesMessage mm;
MODES_NOTUSED(c);
memset(&mm, 0, sizeof(mm));
if ((*p == '1') && (Modes.mode_ac)) { // skip ModeA/C unless user enables --modes-ac
msgLen = MODEAC_MSG_BYTES;
} else if (*p == '2') {
msgLen = MODES_SHORT_MSG_BYTES;
} else if (*p == '3') {
msgLen = MODES_LONG_MSG_BYTES;
}
if (msgLen) {
// Mark messages received over the internet as remote so that we don't try to
// pass them off as being received by this instance when forwarding them
mm.remote = 1;
p += 7; // Skip the timestamp
mm.signalLevel = *p++; // Grab the signal level
memcpy(msg, p, msgLen); // and the data
if (msgLen == MODEAC_MSG_BYTES) { // ModeA or ModeC
decodeModeAMessage(&mm, ((msg[0] << 8) | msg[1]));
} else {
decodeModesMessage(&mm, msg);
}
useModesMessage(&mm);
}
return (0);
}
//
//=========================================================================
//
// Turn an hex digit into its 4 bit decimal value.
// Returns -1 if the digit is not in the 0-F range.
//
int hexDigitVal(int c) {
c = tolower(c);
if (c >= '0' && c <= '9') return c-'0';
else if (c >= 'a' && c <= 'f') return c-'a'+10;
else return -1;
}
//
//=========================================================================
//
// This function decodes a string representing message in raw hex format
// like: *8D4B969699155600E87406F5B69F; The string is null-terminated.
//
// The message is passed to the higher level layers, so it feeds
// the selected screen output, the network output and so forth.
//
// If the message looks invalid it is silently discarded.
//
// The function always returns 0 (success) to the caller as there is no
// case where we want broken messages here to close the client connection.
//
int decodeHexMessage(struct client *c, char *hex) {
int l = strlen(hex), j;
unsigned char msg[MODES_LONG_MSG_BYTES];
struct modesMessage mm;
MODES_NOTUSED(c);
memset(&mm, 0, sizeof(mm));
// Mark messages received over the internet as remote so that we don't try to
// pass them off as being received by this instance when forwarding them
mm.remote = 1;
mm.signalLevel = 0xFF;
// Remove spaces on the left and on the right
while(l && isspace(hex[l-1])) {
hex[l-1] = '\0'; l--;
}
while(isspace(*hex)) {
hex++; l--;
}
// Turn the message into binary.
// Accept *-AVR raw @-AVR/BEAST timeS+raw %-AVR timeS+raw (CRC good) <-BEAST timeS+sigL+raw
// and some AVR records that we can understand
if (hex[l-1] != ';') {return (0);} // not complete - abort
switch(hex[0]) {
case '<': {
mm.signalLevel = (hexDigitVal(hex[13])<<4) | hexDigitVal(hex[14]);
hex += 15; l -= 16; // Skip <, timestamp and siglevel, and ;
break;}
case '@': // No CRC check
case '%': { // CRC is OK
hex += 13; l -= 14; // Skip @,%, and timestamp, and ;
break;}
case '*':
case ':': {
hex++; l-=2; // Skip * and ;
break;}
default: {
return (0); // We don't know what this is, so abort
break;}
}
if ( (l != (MODEAC_MSG_BYTES * 2))
&& (l != (MODES_SHORT_MSG_BYTES * 2))
&& (l != (MODES_LONG_MSG_BYTES * 2)) )
{return (0);} // Too short or long message... broken
if ( (0 == Modes.mode_ac)
&& (l == (MODEAC_MSG_BYTES * 2)) )
{return (0);} // Right length for ModeA/C, but not enabled
for (j = 0; j < l; j += 2) {
int high = hexDigitVal(hex[j]);
int low = hexDigitVal(hex[j+1]);
if (high == -1 || low == -1) return 0;
msg[j/2] = (high << 4) | low;
}
if (l == (MODEAC_MSG_BYTES * 2)) { // ModeA or ModeC
decodeModeAMessage(&mm, ((msg[0] << 8) | msg[1]));
} else { // Assume ModeS
decodeModesMessage(&mm, msg);
}
useModesMessage(&mm);
return (0);
}
//
//=========================================================================
//
// Return a description of planes in json. No metric conversion
//
char *aircraftsToJson(int *len) {
time_t now = time(NULL);
struct aircraft *a = Modes.aircrafts;
int buflen = 1024; // The initial buffer is incremented as needed
char *buf = (char *) malloc(buflen), *p = buf;
int l;
l = snprintf(p,buflen,"[\n");
p += l; buflen -= l;
while(a) {
int position = 0;
int track = 0;
if (a->modeACflags & MODEAC_MSG_FLAG) { // skip any fudged ICAO records Mode A/C
a = a->next;
continue;
}
if (a->bFlags & MODES_ACFLAGS_LATLON_VALID) {
position = 1;
}
if (a->bFlags & MODES_ACFLAGS_HEADING_VALID) {
track = 1;
}
// No metric conversion
l = snprintf(p,buflen,
"{\"hex\":\"%06x\", \"squawk\":\"%04x\", \"flight\":\"%s\", \"lat\":%f, "
"\"lon\":%f, \"validposition\":%d, \"altitude\":%d, \"vert_rate\":%d,\"track\":%d, \"validtrack\":%d,"
"\"speed\":%d, \"messages\":%ld, \"seen\":%d},\n",
a->addr, a->modeA, a->flight, a->lat, a->lon, position, a->altitude, a->vert_rate, a->track, track,
a->speed, a->messages, (int)(now - a->seen));
p += l; buflen -= l;
//Resize if needed
if (buflen < 256) {
int used = p-buf;
buflen += 1024; // Our increment.
buf = (char *) realloc(buf,used+buflen);
p = buf+used;
}
a = a->next;
}
//Remove the final comma if any, and closes the json array.
if (*(p-2) == ',') {
*(p-2) = '\n';
p--;
buflen++;
}
l = snprintf(p,buflen,"]\n");
p += l; buflen -= l;
*len = p-buf;
return buf;
}
//
//=========================================================================
//
#define MODES_CONTENT_TYPE_HTML "text/html;charset=utf-8"
#define MODES_CONTENT_TYPE_CSS "text/css;charset=utf-8"
#define MODES_CONTENT_TYPE_JSON "application/json;charset=utf-8"
#define MODES_CONTENT_TYPE_JS "application/javascript;charset=utf-8"
//
// Get an HTTP request header and write the response to the client.
// gain here we assume that the socket buffer is enough without doing
// any kind of userspace buffering.
//
// Returns 1 on error to signal the caller the client connection should
// be closed.
//
int handleHTTPRequest(struct client *c, char *p) {
char hdr[512];
int clen, hdrlen;
int httpver, keepalive;
char *url, *content;
char ctype[48];
char getFile[1024];
char *ext;
if (Modes.debug & MODES_DEBUG_NET)
printf("\nHTTP request: %s\n", c->buf);
// Minimally parse the request.
httpver = (strstr(p, "HTTP/1.1") != NULL) ? 11 : 10;
if (httpver == 10) {
// HTTP 1.0 defaults to close, unless otherwise specified.
keepalive = strstr(p, "Connection: keep-alive") != NULL;
} else if (httpver == 11) {
// HTTP 1.1 defaults to keep-alive, unless close is specified.
keepalive = strstr(p, "Connection: close") == NULL;
}
// Identify he URL.
p = strchr(p,' ');
if (!p) return 1; // There should be the method and a space
url = ++p; // Now this should point to the requested URL
p = strchr(p, ' ');
if (!p) return 1; // There should be a space before HTTP/
*p = '\0';
if (Modes.debug & MODES_DEBUG_NET) {
printf("\nHTTP keep alive: %d\n", keepalive);
printf("HTTP requested URL: %s\n\n", url);
}
if (strlen(url) < 2) {
snprintf(getFile, sizeof getFile, "%s/gmap.html", HTMLPATH); // Default file
} else {
snprintf(getFile, sizeof getFile, "%s/%s", HTMLPATH, url);
}
// Select the content to send, we have just two so far:
// "/" -> Our google map application.
// "/data.json" -> Our ajax request to update planes.
if (strstr(url, "/data.json")) {
content = aircraftsToJson(&clen);
//snprintf(ctype, sizeof ctype, MODES_CONTENT_TYPE_JSON);
} else {
struct stat sbuf;
int fd = -1;
if (stat(getFile, &sbuf) != -1 && (fd = open(getFile, O_RDONLY)) != -1) {
content = (char *) malloc(sbuf.st_size);
if (read(fd, content, sbuf.st_size) == -1) {
snprintf(content, sbuf.st_size, "Error reading from file: %s", strerror(errno));
}
clen = sbuf.st_size;
} else {
char buf[128];
clen = snprintf(buf,sizeof(buf),"Error opening HTML file: %s", strerror(errno));
content = strdup(buf);
}
if (fd != -1) {
close(fd);
}
}
// Get file extension and content type
snprintf(ctype, sizeof ctype, MODES_CONTENT_TYPE_HTML); // Default content type
ext = strrchr(getFile, '.');
if (strlen(ext) > 0) {
if (strstr(ext, ".json")) {
snprintf(ctype, sizeof ctype, MODES_CONTENT_TYPE_JSON);
} else if (strstr(ext, ".css")) {
snprintf(ctype, sizeof ctype, MODES_CONTENT_TYPE_CSS);
} else if (strstr(ext, ".js")) {
snprintf(ctype, sizeof ctype, MODES_CONTENT_TYPE_JS);
}
}
// Create the header and send the reply
hdrlen = snprintf(hdr, sizeof(hdr),
"HTTP/1.1 200 OK\r\n"
"Server: Dump1090\r\n"
"Content-Type: %s\r\n"
"Connection: %s\r\n"
"Content-Length: %d\r\n"
"Cache-Control: no-cache, must-revalidate\r\n"
"Expires: Sat, 26 Jul 1997 05:00:00 GMT\r\n"
"\r\n",
ctype,
keepalive ? "keep-alive" : "close",
clen);
if (Modes.debug & MODES_DEBUG_NET) {
printf("HTTP Reply header:\n%s", hdr);
}
// Send header and content.
if ( (write(c->fd, hdr, hdrlen) != hdrlen)
|| (write(c->fd, content, clen) != clen) ) {
free(content);
return 1;
}
free(content);
Modes.stat_http_requests++;
return !keepalive;
}
//
//=========================================================================
//
// This function polls the clients using read() in order to receive new
// messages from the net.
//
// The message is supposed to be separated from the next message by the
// separator 'sep', which is a null-terminated C string.
//
// Every full message received is decoded and passed to the higher layers
// calling the function's 'handler'.
//
// The handler returns 0 on success, or 1 to signal this function we should
// close the connection with the client in case of non-recoverable errors.
//
void modesReadFromClient(struct client *c, char *sep,
int(*handler)(struct client *, char *)) {
int left;
int nread;
int fullmsg;
int bContinue = 1;
char *s, *e;
while(bContinue) {
fullmsg = 0;
left = MODES_CLIENT_BUF_SIZE - c->buflen;
// If our buffer is full discard it, this is some badly formatted shit
if (left <= 0) {
c->buflen = 0;
left = MODES_CLIENT_BUF_SIZE;
// If there is garbage, read more to discard it ASAP
}
nread = read(c->fd, c->buf+c->buflen, left);
// If we didn't get all the data we asked for, then return once we've processed what we did get.
if (nread != left) {
bContinue = 0;
}
if ( (nread < 0) && (errno != EAGAIN)) { // Error, or end of file
modesFreeClient(c->fd);
}
if (nread <= 0) {
break; // Serve next client
}
c->buflen += nread;
// Always null-term so we are free to use strstr() (it won't affect binary case)
c->buf[c->buflen] = '\0';
e = s = c->buf; // Start with the start of buffer, first message
if (c->service == Modes.bis) {
// This is the Beast Binary scanning case.
// If there is a complete message still in the buffer, there must be the separator 'sep'
// in the buffer, note that we full-scan the buffer at every read for simplicity.
left = c->buflen; // Length of valid search for memchr()
while (left && ((s = memchr(e, (char) 0x1a, left)) != NULL)) { // The first byte of buffer 'should' be 0x1a
s++; // skip the 0x1a
if (*s == '1') {
e = s + MODEAC_MSG_BYTES + 8; // point past remainder of message
} else if (*s == '2') {
e = s + MODES_SHORT_MSG_BYTES + 8;
} else if (*s == '3') {
e = s + MODES_LONG_MSG_BYTES + 8;
} else {
e = s; // Not a valid beast message, skip
left = &(c->buf[c->buflen]) - e;
continue;
}
left = &(c->buf[c->buflen]) - e;
if (left < 0) { // Incomplete message in buffer
e = s - 1; // point back at last found 0x1a.
break;
}
// Have a 0x1a followed by 1, 2 or 3 - pass message less 0x1a to handler.
if (handler(c, s)) {
modesFreeClient(c->fd);
return;
}
fullmsg = 1;
}
s = e; // For the buffer remainder below
} else {
//
// This is the ASCII scanning case, AVR RAW or HTTP at present
// If there is a complete message still in the buffer, there must be the separator 'sep'
// in the buffer, note that we full-scan the buffer at every read for simplicity.
//
while ((e = strstr(s, sep)) != NULL) { // end of first message if found
*e = '\0'; // The handler expects null terminated strings
if (handler(c, s)) { // Pass message to handler.
modesFreeClient(c->fd); // Handler returns 1 on error to signal we .
return; // should close the client connection
}
s = e + strlen(sep); // Move to start of next message
fullmsg = 1;
}
}
if (fullmsg) { // We processed something - so
c->buflen = &(c->buf[c->buflen]) - s; // Update the unprocessed buffer length
memmove(c->buf, s, c->buflen); // Move what's remaining to the start of the buffer
} else { // If no message was decoded process the next client
break;
}
}
}
//
//=========================================================================
//
// Read data from clients. This function actually delegates a lower-level
// function that depends on the kind of service (raw, http, ...).
//
void modesReadFromClients(void) {
int j;
struct client *c;
modesAcceptClients();
for (j = 0; j <= Modes.maxfd; j++) {
if ((c = Modes.clients[j]) == NULL) continue;
if (c->service == Modes.ris)
modesReadFromClient(c,"\n",decodeHexMessage);
else if (c->service == Modes.bis)
modesReadFromClient(c,"",decodeBinMessage);
else if (c->service == Modes.https)
modesReadFromClient(c,"\r\n\r\n",handleHTTPRequest);
}
}
//
// =============================== Network IO ===========================
//
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